Process for splicing ends of yarns



United States Patent Cfifice 3,367,813 Patented Feb. 6, 1968 3,367,813PROCESS FDR SPLICKNG ENDS F YARNS Winfried T. Holfeld, Wilmington, DeL,astignor to E. H. du Pont de Nernours and Company, Wilmington, Del. acorporation of Delaware No Drawing. Filed Feb. 2, 1965, Ser. No. 4293058 Claims. (Cl. lid-? ABSTRAQT (BF THE DESCLOSURE This invention isconcerned with the splicing of yarns, especially yarns of syntheticfibers. It is particularly concerned with a process of making strong,non-tacky splices of yarns of synthetic fibers in a short period oftime.

Some textile operations, such as tufting for making pile fabrics,require yarns free of knots for economical operation. Tufting is anoperation in which the yarns pass through the eyes of the tuftingneedles, and a knot in the yarn will cause an interruption of tufting.It is common practice to splice tufting yarns by means of a latexadhesive to yield a joint which will pass through the eye of the tuftingneedle. This splicing process is satisfactory for W001 yarns and thesplice can be made readily and will quickly develop strength and becomenon-tacky. However, when this splicing method is used on yarns ofsynthetic fibers, the splices remain wet and tacky for an intolerabletime and develop strength very slowly.

Since the latex adhesives which have been used for splicing wool yarnsdid not result in satisfactory dry splices rapidly for yarns ofsynthetic fibers, other adhesives and other means of cementing the endsof the yarns together have been tried. No other adhesives have beenfound to replace the lattices based on natural rubber or synthetic,rubber-like polymers. Ends of yarns have been fused together by meansdisclosed in Us. Patents 3,040,153 to Seney or 3,055,786 to Hendrix, butthese processes are not suitable for use in the present invention.

It is, therefore, an object of the present invention to provide aprocess of making splices of yarns of synthetic fibers which spliceswill rapidly develop high strength and become non-tacky.

This and other objects are attained in the present invention in whichthere is supplied, to a latex adhesive on the ends of yarn to be joined,a finely divided, waterabsorbing powder, before or after overlapping theyarn ends. The union is then consolidated as by rubbing the splicebetween the fingers. In this simple fashion, the latex is promptlycoagulated and rendered non-tacky, as is now accomplished when usingsuch lattices in splicing wool.

Satisfactory solids for carrying out the present invention include alarge number of finely divided solid materials which will absorb water.The preferred materials will not only absorb water but are positivelycharged particles which will hasten the coagulation of the latex, whichnormally is negatively charged. Thus the colloidal aluminas and otherbasic oxides or hydroxides of metals are most satisfactory for purposesof this invention. One of the preferred materials is a fibrous aluminamonohydrate having the boehmite crystal lattice. The preparation of thisalumina is described beginning at line 15, column 5, of US. Patent2,915,475. Aluminas prepared from aluminum hydroxide or from basic saltsof aluminum are also satisfactory. An amalgamated aluminum can bereacted with water to yield a very finely divided alumina which issuitable, after drying, for use in this invention. Bentonite, Fullersearth and other types of clay can be used if in a very finely dividedstate. Silica of or near colloidal particle size will serve in thepresent invention but is inferior to positively charged aluminas. A fineparticle size silica can be prepared by burning silicon tetrachloride inoxygen. These materials are sometimes called aerogels, and are suitablefor use in this invention. Aluminas can likewise be prepared by burningaluminum trichloride in oxygen. Finely powdered chalk, sometimesreferred to as whiting or french chalk, is also satisfactory. Ifpositively charged lattices are used, then the silicas and clays willpeform more satisfactorily. Boric acid will also function satisfactorilybut may offer a health hazard under some conditions. Salts of polyvalentmetals will quickly coagulate the negatively charged adhesive latexesand can be used alone or with aluminas, silicas or clays to hasten thedevelopment of strong bonds.

Any particle size of the solid power can be employed. However, particlesof micron size or smaller down to an impalpable fineness provide arelatively large surface area per unit weight of powder and may speedthe conversion of the latex to a coagulated, non-tacky body. Thequantity of solids applied need not be regulated. Simple immersion ordipping of the coated fiber ends (or splice) in a container of the drypowder is effective in applying a suitable quantity of the powder. Anyother method of application can be used as well. The powder, of course,must be sufiiciently dry that it retains water adsorption capacity whenused, and may be heated, if desired or necessary, to remove occludedmoisture prior to use.

The invention preferably is practiced with the latex adhesives presentlyused in the textile industry for splicing wool. These can be of anatural or synthetic origin and are used in aqueous dispersion, suitablywith minimum water content. Any other adhesive that will set-up promptlyto a nontacky mass at room temperature upon abstraction of water canalso be used. As already noted, the adhesive and powder can be appliedto yarn ends which are then overlapped, or the yarn splice can first bemade and the adhesive and powder then applied. Preferably, the yarn endsare relatively free from oil and greases during splicing.

The invention will be described further in conjunction with thefollowing examples in which parts and percentages given are by weightunless otherwise indicated or apparent.

EXAMPLE I A 12 denier (1.33-Tex) filament is spun as a bicomponent fiberby the process of US. Patent 3,038,236 to Breen, from the followingpolymer solutions.

Polymer Solution II:

Terpolymer of:

Acrylonitrile 93.6% Methyl acrylate 6.0% 93 Sodium Styrenesulfonate 0.4%Tris(dibromopropyl)phosphate 7 Each solution contains about 29 parts ofthe polymer and 71 parts of dimethylformamide as solvent.

The spun fiber is washed, drawn, crimped, cut into 3 inch (7.6 cm.)staple and dried.

A homofiber is spun from polymer Solution II alone. This fiber afterwashing, drawing (2.3x), crimping, cutting and drying has a denier of 17(1.89Tex).

The bicomponent fiber and the homofiber are blended in equal amounts andspun into a 1.25 Wool run (240-Tex) yarn with 4.5 turns per inch (1.77turns per cm.) Z twist, two plied and twisted 3.0 turns per inch (1.18turns per cm.) S.

Ends of this yarn are spliced by dipping each end up to 0.25 inch (0.6cm.) into a commercial aqueous latex adhesive dispersion designed forsplicing (Bordens Splic-lt). The ends are then dipped into a dry,colloidally fine powder of alumina having the boehmite crystal latticestructure made according to U.S. Patent 2,915,475 to Bugosh, and theends then overlapped 0.5 inch (1.3 cm.) and rubbed between the fingersto entangle the fibers and to distribute the latex. The resulting spliceis strong and non-tacky. Control splices are made in similar manner butwithout using the alumina. The bond strength is determined within oneminute from the time the splice is made. The results for a number ofsplices are shown in Table I below:

TABLE I [Force (in lbs. and kilos) to pull spliced yarns apart]*Average.

The results in this table show that higher strength bonds are formedwhen the alumina is used than when it is not. Moreover, the splices madewith alumina were also non-tacky whereas those without alumina remaintacky for several hours.

EXAMPLE II A denier (1.65Tex) staple fiber of a polyester of ethyleneglycol and terephthalic acid is spun into a 1.25 wool run (240-Tex) yarnand this is two-plied. This twoply yarn is spliced by the methoddisclosed in Example I using the same adhesive with and withoutWaterabsorbing powders. The powders used are an alumina preparedaccording to U.S. Patent 2,915,475 and a silica aerogel made by burningsilicon tetrachloride in oxygen. As in Example I, the yarn ends aredipped first in the latex adhesive dispersion, then in the alumina inone series of experiments and in silica in the other series. The resultsare shown in Table 11 below:

TABLE II.FORCE (IN LBS. AND KILOS) TO PULL SPLICED 4. EXAMPLE III Anylon 66 staple fiber of 3 inch (7.6 cm.) length and 15 denier is cardedand spun into a 1.25 wool run yarn and two-plied to prepare a carpetyarn. This yarn is spliced with the same adhesive and powders used inExample II. Results are shown in Table III below:

TABLE III.FORCE (IN LBS. AND KILOS) TO PULL SPLICED YARN APART Thesemeasurements, like those in Examples I and II, are made within oneminute after the splices are completed. Splices made with adhesive aloneremain tacky for several hours whereas those with alumina or silica arenon-tacky at the end of the splicing operation.

From the foregoing discussion and description it is evident that thepresent discovery constitutes a uniquely simple and effective processfor splicing yarn ends of synthetic fibers. It will be appreciated thatchanges from the details given can be made without departing from thescope of the discovery. For example, any other splicing adhesive orother synthetic fiber can be substituted for those mentioned in theexamples, such materials being well known in the art and commerciallyavailable.

I claim:

1. In the process of joining the ends of two yarns of synthetic fibersin which portions of those ends are arranged in overlapping relationshipand an aqueous latex adhesive dispersion is applied to each yarn endportion, the improvement comprising applying to the aqueous latexdispersion a finely divided, dry desiccant solid material having anelectrical charge opposite to that of the aqueous latex dispersion.

2. The process of claim 1 in which the yarn ends are first coated withsaid aqueous latex dispersion and dry solid material and then areoverlapped to splice the end portions.

3. In a process for splicing ends of two yarns, the steps comprisingarranging the yarn ends in overlapping relationship, dipping theoverlapped end portions in an aqueous latex adhesive dispersion, thencoating the latex covered yarn portions with finely divided drydesiccant solids having an electrical charge opposite to that of theaqueous latex dispersion.

4. A process in accordance with claim 3 in which the aqueous latexdispersion is negatively charged and the dry solids are positivelycharged, and pressure is applied to the solids-containing overlappedends to consolidate the resulting joint.

5. A process of splicing two polyacrylonitrile yarns comprising thesteps of arranging the ends of the yarns in overlapping relationship,coating the yarn ends with an aqueous latex adhesive dispersion thatcontains latex particles that are negatively charged, applying to thesurface of the latex on the yarn ends dry positively charged particlesof a desiccant solid, and consolidating the coated yarn ends to produce9. splice.

6. A process in accordance with claim 5 in which the latex is a naturalrubber latex and in which the dry solids comprise fibrous aluminamonohydrate having the boehmite crystal lattice.

7. A process in accordance with claim 5 in which the latex dispersion isa synthetic polymeric material and the dry solids comprise fibrousalumina monohydrate having 2,121,717 6/1938 Sullivan 117163 the boehmitecrystal lattice 2,169,225 8/1939 Copeman 280-1535 8. A process inaccordance with claim 4 in which the 2,421,363 5/1947 Young 117-- 163 Xsynthetic fibers are composed of a material selected from 2,526,431 10/1950 Strickhonser 117-163 X the group consisting of polyacrylonitrile,nylon and 5 3,257,229 6/1966 Nielsen 117-100 polyesters.

References Cited EARL M. BERGERT, Primary Examiner.

UNITED STATES PATENTS M. L. KATZ, Assistant Examiner. 1,986,974 1/1935Kellog 156158

